diff --git a/electronics/ic_555_timer.py b/electronics/ic_555_timer.py new file mode 100644 index 000000000000..e187e1928dca --- /dev/null +++ b/electronics/ic_555_timer.py @@ -0,0 +1,75 @@ +from __future__ import annotations + +""" + Calculate the frequency and/or duty cycle of an astable 555 timer. + * https://en.wikipedia.org/wiki/555_timer_IC#Astable + + These functions take in the value of the external resistances (in ohms) + and capacitance (in Microfarad), and calculates the following: + + ------------------------------------- + | Freq = 1.44 /[( R1+ 2 x R2) x C1] | ... in Hz + ------------------------------------- + where Freq is the frequency, + R1 is the first resistance in ohms, + R2 is the second resistance in ohms, + C1 is the capacitance in Microfarads. + + ------------------------------------------------ + | Duty Cycle = (R1 + R2) / (R1 + 2 x R2) x 100 | ... in % + ------------------------------------------------ + where R1 is the first resistance in ohms, + R2 is the second resistance in ohms. +""" + + +def astable_frequency( + resistance_1: float, resistance_2: float, capacitance: float +) -> float: + """ + Usage examples: + >>> astable_frequency(resistance_1=45, resistance_2=45, capacitance=7) + 1523.8095238095239 + >>> astable_frequency(resistance_1=356, resistance_2=234, capacitance=976) + 1.7905459175553078 + >>> astable_frequency(resistance_1=2, resistance_2=-1, capacitance=2) + Traceback (most recent call last): + ... + ValueError: All values must be positive + >>> astable_frequency(resistance_1=45, resistance_2=45, capacitance=0) + Traceback (most recent call last): + ... + ValueError: All values must be positive + """ + + if resistance_1 <= 0 or resistance_2 <= 0 or capacitance <= 0: + raise ValueError("All values must be positive") + return (1.44 / ((resistance_1 + 2 * resistance_2) * capacitance)) * 10**6 + + +def astable_duty_cycle(resistance_1: float, resistance_2: float) -> float: + """ + Usage examples: + >>> astable_duty_cycle(resistance_1=45, resistance_2=45) + 66.66666666666666 + >>> astable_duty_cycle(resistance_1=356, resistance_2=234) + 71.60194174757282 + >>> astable_duty_cycle(resistance_1=2, resistance_2=-1) + Traceback (most recent call last): + ... + ValueError: All values must be positive + >>> astable_duty_cycle(resistance_1=0, resistance_2=0) + Traceback (most recent call last): + ... + ValueError: All values must be positive + """ + + if resistance_1 <= 0 or resistance_2 <= 0: + raise ValueError("All values must be positive") + return (resistance_1 + resistance_2) / (resistance_1 + 2 * resistance_2) * 100 + + +if __name__ == "__main__": + import doctest + + doctest.testmod()